[lldb-dap] Adding unit tests for Transport. (#139926)

This adds basic support for testing the Transport class and includes
tests for 'Read' and 'Write'.

Author: ashgti

lldb/unittests/DAP/CMakeLists.txt

@@ -1,6 +1,7 @@
 add_lldb_unittest(DAPTests
   JSONUtilsTest.cpp
   LLDBUtilsTest.cpp
+  TransportTest.cpp
   ProtocolTypesTest.cpp
 
   LINK_LIBS

lldb/unittests/DAP/TransportTest.cpp

@@ -0,0 +1,98 @@
+//===-- TransportTest.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Transport.h"
+#include "Protocol/ProtocolBase.h"
+#include "lldb/Host/File.h"
+#include "lldb/Host/Pipe.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/FormatVariadic.h"
+#include "llvm/Testing/Support/Error.h"
+#include "gtest/gtest.h"
+#include <chrono>
+#include <memory>
+#include <optional>
+
+using namespace llvm;
+using namespace lldb;
+using namespace lldb_dap;
+using namespace lldb_dap::protocol;
+using lldb_private::File;
+using lldb_private::NativeFile;
+using lldb_private::Pipe;
+
+class TransportTest : public testing::Test {
+protected:
+  Pipe input;
+  Pipe output;
+  std::unique_ptr<Transport> transport;
+
+  void SetUp() override {
+    ASSERT_THAT_ERROR(input.CreateNew(false).ToError(), Succeeded());
+    ASSERT_THAT_ERROR(output.CreateNew(false).ToError(), Succeeded());
+    transport = std::make_unique<Transport>(
+        "stdio", nullptr,
+        std::make_shared<NativeFile>(input.GetReadFileDescriptor(),
+                                     File::eOpenOptionReadOnly,
+                                     NativeFile::Unowned),
+        std::make_shared<NativeFile>(output.GetWriteFileDescriptor(),
+                                     File::eOpenOptionWriteOnly,
+                                     NativeFile::Unowned));
+  }
+
+  void Write(StringRef json) {
+    std::string message =
+        formatv("Content-Length: {0}\r\n\r\n{1}", json.size(), json).str();
+    ASSERT_THAT_EXPECTED(input.Write(message.data(), message.size()),
+                         Succeeded());
+  }
+};
+
+TEST_F(TransportTest, MalformedRequests) {
+  std::string malformed_header = "COnTent-LenGth: -1{}\r\n\r\nnotjosn";
+  ASSERT_THAT_EXPECTED(
+      input.Write(malformed_header.data(), malformed_header.size()),
+      Succeeded());
+  ASSERT_THAT_EXPECTED(
+      transport->Read(std::chrono::milliseconds(1)),
+      FailedWithMessage(
+          "expected 'Content-Length: ' and got 'COnTent-LenGth: '"));
+}
+
+TEST_F(TransportTest, Read) {
+  Write(R"json({"seq": 1, "type": "request", "command": "abc"})json");
+  ASSERT_THAT_EXPECTED(
+      transport->Read(std::chrono::milliseconds(1)),
+      HasValue(testing::VariantWith<Request>(testing::FieldsAre(
+          /*seq=*/1, /*command=*/"abc", /*arguments=*/std::nullopt))));
+}
+
+TEST_F(TransportTest, ReadWithTimeout) {
+  ASSERT_THAT_EXPECTED(transport->Read(std::chrono::milliseconds(1)),
+                       Failed<TimeoutError>());
+}
+
+TEST_F(TransportTest, ReadWithEOF) {
+  input.CloseWriteFileDescriptor();
+  ASSERT_THAT_EXPECTED(transport->Read(std::chrono::milliseconds(1)),
+                       Failed<EndOfFileError>());
+}
+
+TEST_F(TransportTest, Write) {
+  ASSERT_THAT_ERROR(transport->Write(Event{"my-event", std::nullopt}),
+                    Succeeded());
+  output.CloseWriteFileDescriptor();
+  char buf[1024];
+  Expected<size_t> bytes_read =
+      output.Read(buf, sizeof(buf), std::chrono::milliseconds(1));
+  ASSERT_THAT_EXPECTED(bytes_read, Succeeded());
+  ASSERT_EQ(
+      StringRef(buf, *bytes_read),
+      StringRef("Content-Length: 43\r\n\r\n"
+                R"json({"event":"my-event","seq":0,"type":"event"})json"));
+}